1. Field of the Invention
This application relates broadly to mounting systems for sound suppressors for firearms. More particularly, it concerns an improved latch system for sound suppressors for use with M4 Series Carbines, M16 Series rifles and other military and commercial automatic, semi-automatic and bolt action firearms.
2. Description of the Prior Art
The M4 Series Carbine and the M16 Series Rifles all use a common flash hider that has some considerable tolerance range for its outside diameter. This tolerance is a major factor in ensuring proper alignment occurs with the bore thru the suppressor baffles and the actual path of the projectile as it travels thru this bore when a sound suppressor is attached to the flash hider by various means. As a result of this tolerance factor, the bore hole through the suppressor usually has to be enlarged when compared to a suppressor using a screw thread attachment method or a proprietary flash hider using much tighter tolerances on the outside diameter of the proprietary flash hider. A number of different mounting systems that allow attachment of a sound suppressor to the standard M4 Series Carbine, M16 Series Rifle and commercial equivalent style flash hiders are known. However, they all have problems including the length of time it takes to attach/detach the suppressor from the flash hider, excessive steps or movements to attach/detach the suppressor, poor support and insufficient bearing surfaces of the mount interface to the flash hider, inability to remove when the suppressor is hot, and excessive thermal transfer to the latch from the mount and the suppressor body. U.S. Pat. No. 4,510,843 (Rabatin) discloses the use of a cam-operated system that compressed lugs on an integral collet into the two grooves on the flash hider common to both M4 Series Carbines and M16 Series Rifles. The main problem with this system is that the collet fingers are basically a form of flat spring and because they surround and are in direct contact with the flash hider, there is considerable transfer of heat to the collet fingers. During prolonged weapon firing the temperature of the collet fingers reaches a point, which is dictated by their heat treatment and metallurgical properties, where the spring characteristics of the collet fingers will become reduced resulting in failure of the fingers to retract out of the flash hider and thus locking the suppressor to the firearm. Rabatin used a gas tube positioned inside the flash hider in an attempt to minimize the effects of heat on the collet fingers. In a second U.S. Pat. No. 6,385,891, Rabatin used a conical pilot in yet another attempt to minimize the effects of gases on the collet fingers. U.S. Pat. No. 5,773,746 (Vaden) disclosed the use of three pivoting fingers that are locked into position by the use of two rotating collars, one positioned on the outside of the mount and the other on the inside. The main problem with the Vaden approach is the inability to activate the lock when the suppressor is hot without the use of special tools or heat resistant materials to protect the operator's hands. Additionally Vaden utilizes a long thread engagement on the rotating collars so it takes considerable motion and time to lock/unlock the system. G.B. Patent 2242476 (Felton) disclosed a mounting system that used a U-shaped cut-out in a locking collar to accommodate various flash hiders including the M4 Series Carbine and M16 Series Rifle flash hider. The collar was tightened against the rear of the flash hider by tightening up the suppressor and the collar to the sound suppressor against the front end of the flash hider. While this mount is secure, the three main problems are the excessive time to attach/detach, the inability to remove a hot suppressor without tools or thermal protection for the operator and the collar being a separate part which is therefore prone to loss. WO 2007/069086 (Brugger) discloses a mounting system that uses a locking gate coupled with a rotation lock and a gate lock to secure the sound suppressor to a flash hider or modified barrel. The problem with this mounting system is that the steps to mount and dismount the suppressor are numerous. First a rotation lock has to be pushed rearward and then the suppressor is rotated about three turns to disengage the suppressor from the mount. Next a gate lock is then pushed forward to disengage a lock pin from the gate, with the gate then being lifted upwards. The suppressor is then slid over the flash hider and the gate is then pushed down and the gate lock is then reengaged. The suppressor is then rotated to lock the suppressor against the front of the flash hider. These many steps are repeated in reverse order to dismount the suppressor.
The present invention solves these problems by the provision of a latch mounting system for use with an M4 Series Carbine, M16 Series Rifle or commercial equivalent rifle that uses a primary latch plate that moves in a vertical plane in conjunction with a secondary latch that pivots about a point on the primary latch plate and produces a downward locking force to secure the primary latch plate to the flash hider. The primary latch interfaces with and locks into the two circular grooves on the M4 Series Carbine, M16 Series Rifle or commercial equivalent flash hider while at the same time indexing the suppressor rotationally against one of the wrench flats on that flash hider. For the secondary latch to engage, the primary latch must be in its fully down position. The secondary latch rotates around a pivot pin which is anchored to the primary latch and mirror image protruding surfaces mate with a path machined into the suppressor's rear support, causing the lower arms of the secondary latch to deflect downward as the protruding surfaces rotate past center and then lock into a small depression machined as part of said path. A small captive compression spring in the vertical primary latch plate applies a force against the flash hider as the primary latch plate is pushed downward; biasing the flash hider towards the bores in the rear and front supports which interface with the flash hider. The force applied by the spring is sufficient to hold the entire suppressor in this biased attitude and thus takes up any diametrical clearance between the flash hider and the bore for the flash hider within the sound suppressor. While the centerline of the flash hider and the centerline of the suppressor are slightly offset, there is minimal angular deviation between these two centerlines. Thus the front of the suppressor does not droop downward due to the effects of gravity which, if it occurred, would necessitate having a larger bore thru the suppressor to prevent the projectiles that pass thru it from striking said bore.
The present invention also solved a problem that exists with the Knight's Armament M4QD and NT4 suppressors. The latch plates on those suppressors move vertically to unlock from a special flash hider. In their fully unlocked position, these latch plates can pivot to a sufficient angle relative to the vertical track within the suppressor such that the latch plate wedges, inhibiting its downward movement. By cutting the track lower into the suppressor and making the latch plate longer, the current design can no longer deflect far enough off axis to its vertical track to bind and thus inhibit its downward travel as locking occurs.